Spark-plug



H. E. GILL.

SPARK PLUG.

APPLICATION FILED OCT. 9, 191a.

1,392,933, Patented 001. 11, 1921.

lllll avwemtoz UNITED STATES PATENT OFFICE.

HORACE E. GILL, OF YONKERS, NEW YORK, ASSIGNOR TO FAN FLAME SPARK PLUG 00., OF YONKERS, NEW YORK, A CORPORATION OF NEW YORK.

SPARK-PLUG.

Specification of Letters IPatent.

Patented Oct. 11, 1921.

To all tukom; it may concern:

Be it known that I, HORACE E. GILL, a citizen of the United States, residing at Yonkers, in the county of Westchester and State of New York, and having a ostoffice address at #217 McLean Ave, on-

kers, New York, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a full, clear, and exact specification.

My invention relates to improvements in spark plugs, and particularly to the use in connection therewith of a new form of gas tight gasket by which the likelihood of breakage of the porcelain insulator is very largely reduced. In the construction of standard spark plugs, a porcelain insulator is used of a generally cylindrical form and provided about midway of its length with an annular enlargement, the insulator being clamped between the two parts of a metal shell and two gaskets being employed for preventing the leakage of gas between the shell and said insulator. These gaskets are located above and below the annular enlargement of the insulator and have heretofore been made of thin copper or other sheet metal with a suitable filling of asbestos. In cross section such gaskets as heretofore made are shaped like a trough with the asbestos filling inserted therein and facing outwardly. In other words, such gas kets have been in the form of small annular troughs with asbestos or other resilient circumferences. In clamping theparts of such a spark plug together, as heretofore constructed, the metal sections of the shell have compressed the metal of the gaskets into tight engagement with the enlarged portion of the insulator and especially have forced the metal of the gaskets into very tight and intimate engagement with the insulator at the point or angle where the said enlarged portion meets the cylindrical body of the insulator. By reason of this tight engagement made necessary to secure a gas tight joint, and also by reason of changes in temperature in use there is danger of the insulator becoming cracked particularly in line with the upper gasket, and of course when such a crack or break occurs the spark plug has to be discarded.

In an examination of many hundreds of' cracked porcelains I have observed that a very large part of them cracked and broke in line with the upper gasket. In order to overcome this difficulty, I make use of a gasket above the enlargement of the porcelain and preferably below the same also, in which the asbestos or other elastic filling is reversely arranged; or in other words, in which the asbestos faces inwardly instead of outwardly. In this way when applied in position and pressure imposed thereon so as to deform the same, the as. bestos packing will be squeezed out and an elastic material will be brought into contact with the porcelain instead of a hard, practically non-elastic metal as with [present practice. In this way I secure even a better joint than is now possible so far as its gas tight character is concerned, and at the same time I very materially reduce the danger of breakage and cracking of the insulator owingto the elastic nature of the pressure imposed upon it. In fact the improvement is so marked as practically to reduce entirely the danger of cracking the insulator which has heretofore been a potent source of annoyance and expense in connection with spark plug manufacture.

In order that my invention may be better understood, attention is directed to the accompanying drawing forming. part of this specification and in which Figure 1 is a cross sectional view of a portion of a standard s ark plug on an enlarged scale showing t e present manner of arranging the gaskets therein; and Fig. 2, a similar view 1 lustratin'g" my improvements.

Referring first to Fig. 1, the insulator 1 is made of porcelain in the usual way and the gasket is' contains the usual central electrode 2. The

insulator 1 is formed with the enlargement 3 as heretofore and is contained within a shell composed of a lower part 4 and an upper part 5 screwed therein. Gaskets 6 and 7 have been arranged as shown between the parts of the shell 4-5 and the enlargement 3. Under present practice these gaskets are arranged as illustrated being formed of a thin sheet of copper with a filling 8 of asbestos or similar elastic material. Asnnow made the gaskets are now arranged as shown in Fig. 1 with the asbestos facing outwardly so that the metal part of each gasket when the sections 4 and-5 are screwed together is forced tightly against the porcelain and breaks or cracks are likely to form therein, substantially as indicated by the dotted lines 9 and 10. Ordinarily breakages at the line 9 coincident with the upper gasket are far more numerous than those at the line 10 corresponding to the lower gasket.

Referring to the Fig. 2, I assemble all parts together in the same way as in Fig. 1, except that the upper gasket 7 is reversed as is preferably also the case with the lower gasket 6. With this construction the asbestos 8 faces inwardly instead of outwardly so that when pressure is applied, squeezing the sections 4 and 5 together, an elastic material presses against the porcelain instead of a hard, unyielding material as in Fig. 1. In this way I practically do away entirely with breaks and cracks in the porcelain and at the same time it becomes possible to screw the sections 4 and 5 more tightly together than at present so as to insure a tighter joint between the shell and porcelain.

Having now described my invention, what I claim as new therein and desire to secure by means of Letters Patent is as follows:

1. In a spark plug, the combination with a vitreous insulator provided with an integral annular enlargement and a two-part shell surrounding the same, of a single gasket interposed between said shell and insulator and comprising an annular metal trough with an elastic packing therein, the

exposed face of said packing facing inwardly and being forced into tight and intimate contact with the vitreous insulator adjacent to the shoulder formed by said enlargement and thus constituting the packed joint between the insulator and shell, substantially as set forth.

2. In a spark plug, the combination with a vitreous insulator provided with an integral annular enlargement, and a two-part shell surrounding the sa1ne,of a single gasket interposed between said shell and insulator above the enlargement and a single gasket interposed between said shell and insulator below the enlargement, each of said gaskets comprising an annular metal trough with an elastic packing therein, the exposed faces of said packings facing inwardly and being forced into tight and intimate contact with the vitreous insulator adjacent to the shoulder formed by said enlargement and thus constituting the packed joints between the insulator and shell, substantially as set forth.

This specification signed and witnessed- 

